1Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006, India2Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570006, India3Department of Studies in Microbiology, University of Mysore, Manasagangotri, Mysore 570006, India

Received 30 September 2013; Revised 8 December 2013; Accepted 14 February 2014; Published 19 May 2014